Automatic sprinkler or fire extinguisher



Oct. 29, 1929. J. TAYLOR AUTOMATIC SPRINKLER 0R FIRE EXTINGUISHER Fi led March 9. 1926 b Fig.8

Patented Oct. 29, 1929 i UNITED STATES PATENT OFFICE I JOHN TAYL'SR, OE MANCHESTER, ELtGLAN 'D 'AUTO'MATIG SPRINKLER 0. 3, FTRE EXTINGUISHE R Application filedMarch 9, 1926, Serial No. 93,511, and in Great Britain May 27, 1925.

This invention relates to automatic sprinbursting pressure. The thinned wall, in conklers or fire extinguishers of the type in which junction with its increased diameter, which a frangible vessel or bulb made of glass is presents a larger area to the bursting presemployed as a strut to support the sprinkler sure, provides a relatively weak belt between 5 valve, the said vessel or bulb containing volathe ends of the vessel or bulb which more 55 tile or otherliquichwhich, when sufficiently readily [shatters than the remainder of the heated, bursts the vessel, so allowing the vessel when bursting ofthe vessel occurs, sprinkler valve to open; thus obviating any tendency of the wall to The use of the said frangible glass vessels split in the longitudinal direction: as freor bulbs involves a dilliculty due to the conquently experienced with cylindrical vessels. 60 ditions to be fulfilled, namely, (1) the vessel Blowing the vessel or bulb in amould has or bulb shall provide a strong strut to sup also the important advantage that any port the valve and the vessel or bulb shall, striations which may have been formed in when it bursts, be entirely shattered so that the act of drawing the glass tube from which the support for the valve is entirely removed the vessel or bulb is made, are effectively 65 and the broken pieces of glass are carried removed and the bulb wallmade more homoaway and do notlodge in the sprinkler degeneous. flector which would spoil the water distri- The vessel or bulb is, duringmoulding, bution. I formed with a flat seat at one or both ends The object of my present invention is for conveniencein mounting the vessel or 70 to provide an improved frangible glass vessel bulb in the sprinkler and for giving stability or bulb which shall fully meet the necessary to it as a strut. A vessel orbulb produced acconditions whilst being readily produced. cording to my invention has its dimensions My invention comprises a frangible glass true to a high degree of accuracy. y i

vessel or bulb produced from a tube which The mould in which the glass tube is blown, is blown in a suitable mould so as to belly as 5 before described, may provide for the out and thin the tube (which has been preformation of projecting cylindrical, helical, viously closed at one end) and make a bulb or other bands or ribs around the vessel or of barrel shape. bulb. 'As a consequence ofjthe somewhat My invention. further comprises theforabrupt change of the contour of the wallsc mation during the blowing process of a pro-j of the vessel or bulb where such bands or jecting belt-like part around the barrel shaped ribs occur, stresses are induced at these parts frangible vessel. I which are greater than the normal stress and My invention further comprises the drawwhen the bulb bursts there is a strong ten- 3 ing out of a glass tube closed at one end dency forlthe lines of fracture to follow the as and the moulding of the drawn out tube so said bands or ribs and the possibility of the that it has one or more bulged bands or bellied vessel or bulb splitting longitudinally instead portions thereon of reduced thickness of glass of being completely shattered, is thereby furand flattened portions at one or both ends. ther minimized. I i i i, v 49 In carrying my invention into efiect in one In order to ensure that the pressure imconvenient manner, I take a piece of glass posed on thebulb at its ends when in position tubing of the desired length and close or in the sprinkler head shall-be effectively carseal it at one end. The other 'end can be ried by the flattened ends of the bulb and drawn down toa reduced diameter. The vesnot byany'seam or like raised edge which i sel or bulb so formed is then blown in a suit may be formed due to the blowing of the bulb able mould so that its walls are bellied out ina split mold, I may provide a cross groove to produce a vessel of barrel shape. During or recess in the parts which bear upon the the blowing process, the thickness of the glass ends of the bulb, and in order to facilitate is necessarily reduced, so reducing the the correct placing of the bulb ends in the strength of the vessel or bulb for resisting said grooved or recessed parts, I may prolee vide for the formation of a marked or sub stantial ridge or seam across each flat end of a bulb, the said ridge or seam occurring at the position of the split or jointin the mould.

Referring to the accompanying sheet of drawings H Figure 1 is an elevation and Figure 2 a sectional elevation illustrating a typical sprinkler head in which a frangible vessel or bulb is employed. These figures also show one of my improved bulbs in position in the sprinkler.

Figures 3 to 7 illustrate five different forms of bulb produced in accordance with my in vention. Figure 8 is. a plan view of the bulb shown in Figure 7. r

The same reference letters in the ClliIQIGIlt views indicate the same or similar parts.

The sprinkler comprises a valve (2; carried by a cap 5 which rests on the hub 0 supported by the hollow cone (Z. c is the usual sprayer fitting.

The bulb 0 shown in Figures 1 and 2 has been produced froma cylindrical piece of glass tube blown in a mould as before described so that it has the barrel shape. illustrated. It has also been formed with flat portions at each end to bear against the cap I) and the support (5 and has. a belt like projecting ridge f produced during the blowing process, and therefore consisting of thinned material.

Figures 3,4,5. and 7 indicate by the dotted line it how the expansion undergone by the original cylindrical tube thinned the glass to an unequal extent, making it thinnest midway between the flat ends where the stress is re-' ceived. This thinnest zone extends peripherally around the barrel and is where the glass first yields when burstby expansion of liquid within. InFigure 4 the circumference of the most bulging part of the barrel shape, at h, is about one and a half times the circumference of the part of the same wall it near the end of the barrel shape. As both were of equal thickness in the original cylindrical stock, that which has become the longer has also be come thinned proportionately and constitutes a medial peripheral zone'of weakness having only two-thirds the strength of the end portion h of the same bulge. The glass of the projecting ridge f in Figs. 5, 7 is even thinner,

because glass of the same original thickness is there further extended in length. Therefore a growing expansive pressure of contained liquid, uniform in all directions, first becomes able to break the glass in the zone or belt of weakness h or f which runs'around the vesselmidway between the elements a and (Z, and

by breaking the vessel along that zone, in a fracture which does not run in the direction of the struts compressive stress, ensures that no fragment of glass can be large enough to reach from end to end and thus obstruct the water distribution from valve a. In fact, the

name tothis specification.

belt f becoming so abruptly thinner than the wall adjacent to it, makes a tendency for sections of glass to be blown out in the initial breaks in which case the remaining half barrel fragments are thrust together by the pent up water or air behind valve a, with a shock which tends the more certainly to shatter both of them into smaller fragments.

In the construction shown in Figure 3, there is a fiat portion at one end only of the bulb and the latter has no belt. In Figure 4, the bulb has flattened portions at both ends, as in Figure 2. The bulb shown in Figure 5 resembles that shown in Figure, 2. I

The bulb shown in Figure 6 has helical projecting ribs or bands f formed therein during blowing for the purpose before referred to.

In the construction illustrated at Figures 7 and 8, scams or ridges g are formed across the flattened parts of the ends of the bulb at positions which correspond with the joint in the split mould in which the bulb was blown. The said ridges lit in a corresponding recess Z) which extends across the cap 6, and inasimilar recess (not shown) provided in the support (5 by which the bulb is held in position in the sprinkler head. The said cap 6 and support (Z only bear upon theflat part of the ends of the bulb, not on the said seams or ridges g, so that an even pressure is applied to the glass.

I claim 1. A frangible hollow strut, combined with ed, by expansion, to apply a breaking stress which fractures the wall of the hollow strut, said wall being of barrel shape with an end portion extending inward abruptly toward the EIXlS directly from the end of the bulging part of the wall and constituting a pediment, whereby the compressive stress resisted by the strut may be applied directly to the ends of its bulged wall.

2. A. frangible hollow strut having a closed barrel-shaped wall which is progressilvely thinner from its ends toward its midd e. i

i 3. A frangible hollow strut having a closed barrel-shaped wall which is progressively thinner from its ends toward its middle and having at its middle an encircling external ridge whose thickness is less than elsewhere ofthe barrel.

l. A frangible hollow strut having end sections closed at one end and at their other ends joined together by a ridge section of greater diameter than that of the end sections; the wall of each end sectionbeing bellied outward and progressively thinner from its closed end to the ridge section, and the wall of the latter being thinner than the adjoining edges of the bellied walls.

In testimony whereof I have signed my JOHN TAYLOR.-

v a substance within it which substance is adapt- 

